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• Determine timestamp in mpg video of KLV streams

  22 février 2024, par Joshua Levoy

  I'm currently working with MISP compliant klv data containing mpg videos. I'm able to find the streams containing this data with ffmpeg using the following command

  


  `ffmpeg -v 0 -ss 0 -i "Day Flight.mpg" -map 0:1 -f framecrc  -`


  


  By varying the -ss argument I am able to select for different klv streams by excluding parts of the video, which leads me to believe that ffmpeg is capable of determining how far into the video these klv streams are. I'd very much be interested in finding these timestams of the KLV streams, such that I can create a process by which a misp compliant mpg video can be clipped into smaller segments, for which its relevant MISP-compliant klv data will be preserved.

  


  Is there a way to get ffmpeg to show me the timestamps where these KLV streams begin, and if not, does anyone know of any better approach to determining the position within the video of these klv streams ?

  


  you can obtain the mpg video file containing mpg data that I am using here https://samples.ffmpeg.org/MPEG2/mpegts-klv/Day%20Flight.mpg

  


  Currently I have run the line laid out above and receive the following output :

  


     #software: Lavf58.29.100 #tb 0: 1/90000 #media_type 0: data #codec_id 0: klv 0,          0,          0,        0,      163, 0xc7572adf, S=1,        1, 0x00bd00bd 0,          0,          0,        0,      163, 0xeddd2774, S=1,        1, 0x00bd00bd 0,          0,          0,        0,      163, 0x5c8d29b0, S=1,        1, 0x00bd00bd 0,          0,          0,        0,      163, 0xb7c428f5, S=1,        1, 0x00bd00bd 0,          0,          0,        0,      163, 0x3c3d28a5, S=1,        1, 0x00bd00bd 0,          0,          0,        0,      162, 0x5cdd2898, S=1,        1, 0x00bd00bd

  


  which is useful for determining there are KLV packets within the video but provides me very little in the way of the timestamp where they are relevant. I have other methods of extracting and decoding these KLV values at these locations, but what I'm interested in specifically, is knowing as close as possible the exact timestamps that the KLV streams are referring to within the 3 minute and 20 second video.

  


• Apply effects using ffmpeg [on hold]

  11 décembre 2013, par bindal

  I have used ffmpeg recorder for recording video in my application,
  Through ffmpeg commnad i can trim , rotate and concate my videos but i want to apply some effects like :

  Black & White
  
  Sepia 
  
  Old Movie
  
  Noise 
  
  Brightness
  
  Thermal
  
  Xray
  
  Pencil
  
  Gamma
  
  Contrast
  
  Saturation
  
  Emboss

  Please suggest me any documentation of ffmpeg,

  Thanks
  Bindal

• FFmpeg sws_scale on changed area

  1er octobre 2016, par useprxf

  I was using sws_scale to convert a group of RGB32 images to YUV420 format. Each image is very similar to the previous one and they only differ on a rectangle region Q.

  My question is how to utilize Q to speed up the conversion process ? An additional parameter should be added to sws_scale function.

  sws_scale( ctx, in_plane, in_stride, sliceY, height, out_plane, out_stride, Q){
  
      // parameter out_plane stores the YUV420 data of previous image
  
      Instead of scanning the whole image, scan through rectangle Q{
  
          Do conversion
  
      }
  
  }